A standard escutcheon such as described in German utility model 8,009,457 has a main plate normally made of metal that fits over the projecting parts of the plumbing fixture and that covers the hole in the wall through which the fixture projects, and a cover plate normally made of a colored synthetic resin that serves as an accent and that may also cover up some adjustment or access holes in the main plate. Screws whose heads are colored the same as the cover plate project through the cover plate and the main plate into the plumbing fixture to secure the escutcheon in place.
The disadvantage of such an arrangement is that the screws are easily scratched or damaged during installation, so that they do not match the cover plate perfectly. In a fancy designer installation this is of course intolerable, and getting new screws of the right color can be a problem for the installer.